Prenatal Gliogenesis in the Neopallium of the Rat

110 Pages·1985·4.471 MB·English

by  Prof. Dr. med., Dr. h.c. Joachim R. Wolff, Dr. med. Michael Rickmann (auth.)

Advances in Anatomy
Embryology and eelI Biology
Vol. 93
Editors
F. Beck, Leicester W. RiId, Galveston
R. Ortmann, Köln J.E. Pauly, Little Rock
T.R. Schiebler, Würzburg
Michael Rickmann Joachim R. Wolff
Prenatal Gliogenesis
in the
N eopallium of the Rat
With 29 Figures
Springer-Verlag
Berlin Heidelberg NewYork Tokyo
Prof. Dr. med., Dr. h.c. Joachim R. Wolff
Dr. med. Michael Rickmann
Zentrum Anatomie
Abteilung Klinische Anatornie und Entwicklungsneurobiologie
Kreuzbergring 36, D-3400 Göttingen
ISBN-13 :978-3-540-13849-5 e-ISBN-13 :978-3-642-70081-1
DOI: 10.1007/978-3-642-70081-1
Library of Congress Cataloging in Publication Data
Rickmann, Michael, 1951.
Prenata! gliogenesis in the neopallium of the rat.
(Advances in anatomy, embryology, and eeli biology; vol. 93)
Bibliography: p.
Includes index.
1. Neopallium. 2. Neuroglia. 3. Developmental neurology. 4. Rats-Development.
5. Embryology-Mammals. 6. Mammals-Development.
I. Wolff, Joachim R., 1935-- . II. Title. III. Title: Gliogenesis in the neopalIium
of the rat. IV. Series: Advances in anatomy, embryology, and cell biology; v. 93.
QL801.E67 vol. 93 574.4 s [599.32'33] 84-26857 [QL938.N45]
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CONTENTS
1 Introduction .......... . 1
1.1 Identifleation of Glial CelIs . 2
1.2 Histogenesis of the Neoeortex 4
2 Material and Methods 7
2.1 Animals 7
2.2 Fixation 7
2.3 Standard Preparation of Tissues 8
2.4 Seleetion of Cortieal Region for Analysis 8
2.5 3H-Thymidine Autoradiography 9
2.6 3H-GABA Autoradiography ..... 9
2.7 Golgi Impregnation ......... 10
2.8 Three-Dimensional Reeonstruetions of Eleetron Mierographs 10
2.9 Immunoeytoehemistry........... 11
2.10 Struetural Criteria for Glial and Neuronal CelIs 12
2.11 Text Strueture and Terminology 13
3 Results 15
3.1 Histologieal Differentiation of the Neoeortex 15
3.1.1 Early MarginaI Zone (E 13-E 14) 15
3.1.2 Late MarginaI Zone (E15-E16) 16
3.1.3 Subeortical Zone 18
3.1.4 Cortieal Plate . . . . . 20
3.1.5 Lamina I ...... . 22
3.1.6 Mesenehymal Struetures 23
3.2 First CelIs of the MarginaI Zone 24
3.2.1 Shape of CelIs at E 14 24
3.2.2 MarginaI Contaet CelIs . . . . 25
3.2.2.1 Pial End-feet . . . . . . . . 25
3.2.2.2 Perikaryon and Small Processes 28
3.2.3 IntereelIular Contaets ... . 30
3.3 CelIs of Lamina I ..... . 30
3.3.1 Quieseent Presumptive Astroeytes (E 17-E 19) 30
3.3.1.1 Perikaryon . . . . . . . . . . . 32
3.3.1.2 Pial Process . . . . . . . . . . . 32
3.3.2 Other Nonneuronal CelIs (E 17-E 19) 34
3.3.2.1 Dense N uc1eus CelIs . . . . . . . 34
3.3.2.2 Intermediate Cells . . . . . . . . 36
3.3.3 Cells Containing GFAP and C1-Antigen (E 18-E 19) 37
v
3.3.4 Distinetion between Neuronal and Nonneuronal Cells 40
3.3.5 GABA-Aeeumulating Cells 42
3.3.6 Nonneuronal Cells at E20 and E21 44
3.4 Cells of the Deep Layers 48
3.4.1 Deep MarginaI Zone (E 15-E 16) 48
3.4.1.1 Polymorphie Cells and Mitotie Cells 50
3.4.1.2 Horizontal Neuron-like Cells 50
3.4.1.3 Cellular Processes 52
3.4.1.4 Intereellular Relations 52
3.4.2 Subeortieal Zone (E 17-E22) 54
3.4.2.1 Dense Polymorphie Cells 56
3.4.2.2 Large Glial Preeursors 58
3.4.2.3 Light Horizontal Cells 58
3.4.2.4 Phagoeytes 60
3.4.2.5 Cell Proliferation 60
3.4.2.6 GABA Aeeumulation 64
3.4.2.7 Demonstration of G F AP and C 1-Antigen (E 18, E 22) 64
3.4.2.8 Golgi Impregnation 66
3.5 Nonneuronal Cells of the Cortieal Plate 74
4 Discussion 76
4.1 AnIage of the Pallial Zones 77
4.2 Early Glial Cells with Pial Contaet 79
4.3 Early Separation of Glial and Neuronal Cell Lines 82
4.4 Subeortieal Cell Proliferation 83
4.5 Intereellular Contaets 85
4.6 Maturation of Glial Cells 87
4.7 Summary of Glial Criteria 87
5 Summary 92
6 References 94
7 Subject Index 103
VI
Acknowledgements
The major part of the experimental work was carried out at the Max Planck
Institute for Biophysical Chemistry, Department of Neurobiology (Göttingen),
and was presented by Michael Rickmann in partial fulti11ment of the require
ments of the Doctor of Medicine degree at the U niversity of Göttingen.
The authors thank Prof. M. Schachner for providing the C l-antibodies and
for her great help in the immunohistochemical part of this work.
et),
We gratefully acknowledge the support of Prof. v. Ehrenstein Depart
ment of Molecular Biology, Max Planck Institute for Experimental Medicine
(Göttingen), where the computer reconstructions were done.
We thank Mr. R. Dungan and Mrs. B. Rühlke for their aid with the photo
graphy, and Mrs. U. Kerl for her valuable assistance with preparing the illustra
tions.
We are grateful to Dr. D.G. Amaral for reading earlier versions of the ma
nuscript and for his many valuable suggestions.
VII
1 INTRODUCTION
At the end of the nineteenth century, controversy arose as to precisely when
the first glial cells originate during development of the central nervous system,
and to date, the issue has not been satisfactorily resolved.
His (1889, 1890) noted that, even in the earliest developmental stages of
the germinallayer, there appeared to be two distinct cell types. The cells which
he called Spongioblasten were thought to be glial precursors from which all
mature glial cells derive; Keimzellen, in contrast, were regarded as forming
neurons. His was working on the assumption that the very first preneurons1
migrate into a preexisting framework of glial eelIs. In contrast to this view,
Schaper (1897) regarded both Keimzellen and Spongioblasten as belonging to
a common population of proliferating and pluripotent stem cells which begin
differentiation into glial and neuronal cells at late developmental stages. It is
this latter view which is the basis of the most recent studies on the subject
(e.g., Caley and Maxwell1968a, 1968b; DeVitry et al. 1980).
The concept of one common stem cell seemed to be supported both by
experiments using 3H-thymidine autoradiography (Fujita 1963, 1965b, 1966;
Sauer and Walker 1959; Sidman et al. 1959) and by ultrastructural studies (Fu
jita 1966; Hinds and Ruffet 1971; Wechseler and Meller 1967) indicating that
structural differences, which His presumably used to define his two cell types,
could be related to different stages of the mitotic cycle.
Given that neurons and glia arise from one common stem cell, it became
generally accepted that the first glial cells originate after neurons cease to be
formed (Das 1979; Fujita 1965 a, 1973, 1980). This view is largely based on
3H-thymidine experiments showing highly labeled glial cells primarily at late
stages of development (Berry and Rogers 1966; Brueckner et al. 1976; Tsai
et al. 1981). These experiments, however, used long survival times after injections
and therefore, rather than determining the time of origin of glial cells which
continue to divide, they in fact identified the "birth date" of that fraction
of glial cells which underwent their last mitosis after injection (see Sect. 2.5).
Assuming that young glial cells behave similarly to the growth fraction of adult
glial cells (Korr 1980, Hajos et al. 1981), undergoing several cell divisions before
becoming postmitotic, 3H-thymidine autoradiography would tend to underesti
mate the time of origin of the glial cellline (Sidman 1970).
One class of cell which has attracted substantial interest among neurobiolog
ists is that of the radial glia. Radial glial cells resemble the ependymal cells
described by Cajal (1959) and the epithelial cells of Retzius (1893b, 1894a).
These authors pictured cells with bodies residing close to the ventricle and
1 In this study, "preneurons" are to be considered postmitotic young neurons (see Sect. 2.11).
1
with one long process extending to the pia mater which had short side branehes
along its eourse. In the prenatal neoeortex of rhesus monkeys, which have
a gestation period of 165 days, radial glial eelIs were deteeted in Golgi prepara
tions by embryonie day (E) 48 (SchrnecheI and Rakie 1979a) and in immunohis
toehemieal preparations of glial fibrilIary acidie protein (GFAP) by E47 (Levitt
and Rakie 1980). In the brain of human fetuses, radial glial eelIs beeome deteet
able by the tenth week in GFAP preparations and by the 12th week in Golgi
material (Antanitus et al. 1976; Choi and Lapham 1978). In early studies of
the rat neoeortex, radial glial eelIs eould not be shown before birth by GFAP
immunofluoreseenee (Bignami and Dah11974a, b; Raju et al. 1981). However,
in more reeent studies, using the unlabeled antibody (peroxidase-anti-peroxi
dase, PAP) method, these glial eelIs were deteeted at E18 in mouse neoeortex
(Woodhams et al. 1981).
It has been proposed that radial glial eelIs aet as guiding struetures for
migrating preneurons (Levitt and Rakic 1980; Nowakowski and Rakic 1979;
Rakie 1971, 1972, 1975, 1982; Rakie et al. 1974; Sidman and Rakic 1973).
Reeently, it has been demonstrated that the ventrieular layer ofmonkey neoeor
tex eontains not only radial glial eelIs but also GFAP-positive mitotic figures
(Levitt et al. 1981, 1983). These data support, to some extent, the concept of
Spongioblasten proposed by His (1889,1890, 1904). The signs of glial differentia
tion seem to appear during the period of inereased produetion and migration
of neurons. Moreover, a detailed investigation of the kinetics of eelI division
(Waeehter and Jaensch 1972) revealed that the ventricular zone contains two
populations of dividing eelIs throughout neurogenesis, i.e., even before the main
period of neuron produetion. Thus, as we began our studies on glial develop
ment, it seemed probable that some elasses of glial eelIs originate at very early
stages of neuraI development, although the eontroversy surrounding this issue
eontinues (Fujita 1980).
1.1 Identifleation of Glial eelIs
In view of the problems outlined above, we considered that additional eriteria
were needed to identify glial precursors at all developmental stages. In the
undamaged brain, neuroeetodermal eelIs ean be readily distinguished from me
senehymal eelIs by their position and strueture. In addition, the bulk of available
evidenee suggests that oligodendroeytes do not appear in the neoeortex before
birth (see, for example, Davison et al. 1966; Sturroek 1976). Therefore, we
restrieted the present investigation of neopallial eelIs to establishing morphologi
eal eriteria for young astroglial eelIs and for distinguishing them from immature
neurons.
In principle, the origin of the glial eelIline should be loeated where undiffer
entiated neuroepithelial eelIs are, for the first time, eommitted for glial differenti
ation. The glial eharaeter of these eelIs, however, eannot be reeognized before
they have developed glial eharaeteristics. Thus, the eriteria which were most
useful for us should appear within the shortest possible lateney time after eom
mitment and should stilI be deteetable in adult astroeytes.
A variety of presumptive glial eelI types has been deseribed on the basis
of their ultrastrueture (PhilIips 1973; Sturroek 1974,1975,1976; Vaughn 1969).
2
Such eelIs were regarded as glial beeause they were deteeted in the white matter,
which was thought to be devoid of neurons. However, the white matter be10w
the neoeortex does, in faet, contain neurons (Rickmann et al. 1977), and, in
addition, none of the ultrastruetural features deseribed in these reports seems
to be exc1usively glial (see Seet. 2.10). In view of the limitations of a purely
ultrastruetural study, we sought additional eharaeteristics of early glial eelIs
whieh eould be inc1uded in an ultrastruetural analysis and which would alIow
young glial eelIs to be distinguished from immature neurons and stern eelIs
present at the same time.
Our initial observations suggested that the three-dimensional strueture of
neuroeetodermal eelIs and their eontaet relation with mesenehymal surfaees
seem to be the most favorable eandidates for such eriteria. Undifferentiated
neuroepithelial eelIs eontaet the ventrieular surfaee and also, at least in the
interphase of their mitotic eyc1e, the mesenehymal struetures (pial surfaee)
(Hinds and Hinds 1979; Hinds and Ruffet 1971). Tanyeytes and radial glial
eelIs resemble undifferentiated neuroepithelial eelIs in that they maintain the
primitive eontaet relation with the basal and apieal surfaees of the neuroepithe
lium 2. At the same time, they folIow a pattern of differentiation similar to
that of astroeytes, inc1uding lameHate expansions of their plasma membrane,
numerous glyeogen partic1es, and the presenee of GFAP (Güldner and Wolff
1973; Levitt and Rakic 1980; Peters and Feldman 1973; Sehmeehel and Rakie
1979a). However, Roessmann et al. (1980) have questioned whether tanyeytes
and radial glial eelIs are identical eeH types. In eontrast, adult neurons generalIy
do not eontaet the ventrieular surfaee or mesenehymal tissue, exeept in a few
speeial cases. Astroeytes are different from all these eelI type s in that they
regularly withdraw from the ventrieular surfaee but form eontaets with the
basal membrane of blood vesseIs and/or the pia mater.
The eapaeity of eelI division appears to be another feature where by young
glial eelIs ean be distinguished from preneurons. By using 3H-thymidine autora
diography it has been shown that, even in the adult central nervous system,
there remains a growth fraetion of proliferating glial eeHs (Kaplan and Hinds
1980; Korr et al. 1973; Korr 1980; Mori and Leblond 1969; Smart and Leblond
1961). During development, the proportion of aetively dividing glial eelIs seems
to deerease, while periods of temporary mitotie inaetivity of individual eelIs
inerease (Baseo 1981; Korr 1980). Radial glial eelIs, the earliest glial eelIs identi
fied so far, undergo periods of arrested proliferation (SchrnecheI and Rakie
1979 b). Thus, a struetural eharaeterization of labeled eelIs using short survival
times after 3H-thymidine injeetion ean be very useful, sinee the proliferative
eharaeteristies of young glial eelIs as welI as their struetural differentiation dur
ing periods of mitotie arrest ean be studied.
The number of available immunoeytoehemieal glial markers is rapidly in
ereasing (Eng and Bigbee 1978; Roots 1981; Varon and Somjen 1979), and
we have found that this methodology ean be usefulIy applied to the identifieation
of early glial eelIs. However, as for the other methods deseribed so far, eaution
must be exereised when applying immunoeytoehemieal methods in early devel
opmental stages. In partieular, antigens whieh appear early in the neuroepithe
lium and whieh are still present in adult glial eeHs - for example, vimentin,
2 The neuroepithelium forms its apieal surfaee toward the ventride and eontaets mesenehymal
struetures (derivatives of the mesoderm), especially the pia mater, with its basal surfaee.
3
C 1, nonneuronal enolase, and earbonie anhydrase C - do not seem to distinguish
between glial eells and undifferentiated neuroepithelial eells (Dahl et al. 1981;
Linser and Moseona 1981; Marangos and Sehmeehel 1980; Sehmeehel et al.
1978, 1980; Sehnitzer et al. 1981; Sommer et al. 1981). Some glial antigens,
e. g., M 1, may be expressed temporarily during differentiation (Lagenaur et al.
1980; Sehaehner et al. 1982). Other markers, such as GFAP, S100, Ml, 01,
02,03, and 04 (Bignami and Dah11974a, b; Gombos et al. 1971; Sehaehner
et al. 1981; Sommer and Sehaehner 1981; Steward 1975) may appear late, i.e.,
after eonventional morphologieal methods are already eapable of identifying
glial eells (Jaeobson 1978). In addition, antigens shown to be speeifie for either
neurons or glial eells in the adult brain, such as neuron-speeifie enolase, S 100,
and vimentin (Bignami et al. 1982; DeVitry et al. 1980; Dräger 1983), may
even oeeur simultaneously in the same eells during development of speeial brain
regions and eell types. Consequently, staining glial-assoeiated antigens may re
veal not the' newly formed glial eells but rather the maturation of a eell popula
tion whieh has existed for some time.
Problems of immunoeytoehemieal methods may be due to the a priori diffi
eulty of determining their sensitivity (compare Bignami and Dahl 1974a, b
with Woodhams et al. 1981). Furthermore, the visualization of the antigen may
depend on its solubility, as in the ease ofSl00 (Varon and Somjen 1979; Ghan
dour et al. 1981), and even ofGFAP (Ghuens et al. 1980; Jaeque et al. 1980).
In order to avoid these possible pitfalls, we first investigated the development
of neopallial eell types using the conventional morphological methods deseribed
above. Thus, we sought a eharaeterization of eell types which was independent
of immunoeytoehemieal methods. We then tested for the possibility that some
of our eell type s contained glial antigens.
1.2 Histogenesis of the Neocortex
The layers distinguished in the pallium during development have been given
a variety of names (for nomenclatures sinee 1969, see Winkelmann 1977). In
this paper, the nomenclature of the Boulder Committee (1970) is followed.
In the earliest developmental stages, the pallium eonsists of a pseudostratified
epithelium - the "ventrieular zone" of the Boulder Committee. This zone re
mains adjaeent to the ventricle and is the primary zane of proliferation of
the developing teleneephalon. In prineiple, all neoeortieal eells stem from eells
of the ventrieular zone. Glial eells originate from ventrieular eells before they
possess glial features. Henee, ventrieular eells mayeither represent stem eells
whieh ean produee neurons and glial eells at the same time, or they may contain
a predetermined subpopulation of glial eelIs.
In stages B-E, the Boulder Committee demareates a marginaI zone beneath
the meningeal surfaee of the neuroepithelium. This zone is primarily devoid
of eells and eontains only basal processes of ventricular eells through which,
by stage C, axons have been woven.
In stage C, an intermediate zone ean be separated from the ventrieular
and the marginaI zones. This eontains the first immature neurons and their
axons. In stages D and E, however, the intermediate zone is positioned between
the subventrieular zone and the eortieal plate, i.e., it represents the anIage
4